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/*
* EMSA Classes
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_PUBKEY_EMSA_H_
#define BOTAN_PUBKEY_EMSA_H_
#include <botan/secmem.h>
#include <botan/asn1_obj.h>
#include <string>
namespace Botan {
class Private_Key;
class RandomNumberGenerator;
/**
* EMSA, from IEEE 1363s Encoding Method for Signatures, Appendix
*
* Any way of encoding/padding signatures
*/
class BOTAN_TEST_API EMSA
{
public:
virtual ~EMSA() = default;
/**
* Factory method for EMSA (message-encoding methods for signatures
* with appendix) objects
* @param algo_spec the name of the EMSA to create
* @return pointer to newly allocated object of that type, or nullptr
*/
static std::unique_ptr<EMSA> create(const std::string& algo_spec);
/**
* Factory method for EMSA (message-encoding methods for signatures
* with appendix) objects
* @param algo_spec the name of the EMSA to create
* @return pointer to newly allocated object of that type, or throws
*/
static std::unique_ptr<EMSA> create_or_throw(const std::string& algo_spec);
/**
* Add more data to the signature computation
* @param input some data
* @param length length of input in bytes
*/
virtual void update(const uint8_t input[], size_t length) = 0;
/**
* @return raw hash
*/
virtual secure_vector<uint8_t> raw_data() = 0;
/**
* Return the encoding of a message
* @param msg the result of raw_data()
* @param output_bits the desired output bit size
* @param rng a random number generator
* @return encoded signature
*/
virtual secure_vector<uint8_t> encoding_of(const secure_vector<uint8_t>& msg,
size_t output_bits,
RandomNumberGenerator& rng) = 0;
/**
* Verify the encoding
* @param coded the received (coded) message representative
* @param raw the computed (local, uncoded) message representative
* @param key_bits the size of the key in bits
* @return true if coded is a valid encoding of raw, otherwise false
*/
virtual bool verify(const secure_vector<uint8_t>& coded,
const secure_vector<uint8_t>& raw,
size_t key_bits) = 0;
/**
* Prepare sig_algo for use in choose_sig_format for x509 certs
*
* @param key used for checking compatibility with the encoding scheme
* @param cert_hash_name is checked to equal the hash for the encoding
* @return algorithm identifier to signatures created using this key,
* padding method and hash.
*/
virtual AlgorithmIdentifier config_for_x509(const Private_Key& key,
const std::string& cert_hash_name) const;
/**
* @return a new object representing the same encoding method as *this
*/
virtual std::unique_ptr<EMSA> new_object() = 0;
/**
* @return the SCAN name of the encoding/padding scheme
*/
virtual std::string name() const = 0;
};
/**
* Factory method for EMSA (message-encoding methods for signatures
* with appendix) objects
* @param algo_spec the name of the EMSA to create
* @return pointer to newly allocated object of that type
*/
BOTAN_TEST_API EMSA* get_emsa(const std::string& algo_spec);
/**
* Returns the hash function used in the given EMSA scheme
* If the hash function is not specified or not understood,
* returns "SHA-512"
* @param algo_spec the name of the EMSA
* @return hash function used in the given EMSA scheme
*/
BOTAN_TEST_API std::string hash_for_emsa(const std::string& algo_spec);
}
#endif
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